Method and plant for treating lumber



5, 1969 P. A. R. OTTOSSON 3,459,245

METHOD AND PLANT FOR TREATING LUMBER Filed Sept. 23, 1966 United States Patent METHOD AND PLANT FOR TREATING LUMBER Par Axel Rune Ottosson, Nybro, Sweden, assignor to Kahrs Maskiner Aktiebolag, Nybro, Sweden Filed Sept. 23, 1966, Ser. No. 581,514 Claims priority, application Sweden, Sept. 24, 1965, 12,410/ 65 Int. Cl. B27b 1/00; B27c 9/00 US. Cl. 144-312 6 Claims ABSTRACT OF THE DISCLOSURE Examining an incoming log, with photocells to determine the size, and radioscopically to determine quality of it. This information is used to adjust variable band saws get optimum cuts, and to sort the cut portions.

The prevailing method for sawing timber has been, and still is, the gang saw. The saw blades are set up to give a miximum yield from a certain diameter, the logs being sorted and those having a diameter corresponding to the setting of the saw-blades being passed inline through the apparatus, it being necessary to reset the saw blade for logs of a different diameter, and pass available logs of this diameter through the apparatus. It is also conceivable that the logs are sorted with respect to quality,

i.e. logs are received of a certain class or quality and certain diameters sawn just as the quality justifies.

To simplify the setting up of the saw-blades it is more general nowadays to use band saws which are so adapted that the whole of the frame of the band saw can be displaced laterally to the desired extent. (Such an arrangement can be read, for instance, from the Swedish patent specification No. 190,096.) All known sawing methods depart from the principle that all incoming logs are sorted into storage sites according to different quality or sizes, so as to be later sawn according to said quality or size. Such a handling system often requires large storage space and expensive conveying means, as well as being time consuming. The present invention is intended to provide a means for sawing logs without it being necessary to pre-sort the same, yet at the same time maintain the desired yield.

The method according to the present invention is mainly characterized in that each wooden object is passed to examining means for determining the quality and/ or dimensions of the wood, after which the wooden object, without being sorted, is passed to a sawing plant provided with a number of adjustable sawing members, the sawing members being adjusted in accordance with control impulses eminating from a data machine which obtains information signals from the examining means and is so programmed that the desired yield is obtained for each wooden object, depending on its quality and/ or size conditions.

The invention is also characterized by a plant for carrying out the aforementioned method, said plant comprisng a conveyor belt which leads each wooden object past one or more examining means for determining quality and/or size, after which each of said objects is arranged to be gripped at the ends surfaces and, so secured, moved against band saw-blades arranged in pairs, said blades in each pair being adapted displaceably towards and away from each other, in answer to signals obtained from a preprogrammed data machine adapted to be supplied with information signals from the said examining means.

The present invention will be more closely described with reference to an embodiment which is shown on the accompanying drawing, said drawing showing in perspective an apparatus acording to the invention.

3,459,246 Patented Aug. 5, 1969 The apparatus illustrated on the drawing is best explained by describing the path of a wooden object through the plant. The wooden objects 1 are fed via a conveyor 2 to a debarking machine 3 and then to an arrangement 4 for examining the possible existence of stones, metal objects and the like embedded in the wooden object. In the event that a metal object, for example, is embedded in the wooden object-and thus liable to cause damage to the saws included in the system-the arrangement 4 will react and actuate a rejection arrangement 5 which moves the wooden object laterally onto a conveyer 6. Should i the wooden object be free from foreign bodies the said object passes a radioscopic device for determining the quality of the object. Information concerning the quality of the log is passed to the memory in a computer, which will be more fully described below. The log is then displaced laterally onto a conveyor 8 and passed to an arrangement which rotates the log 1 and which comprises a plurality of toothed wheels 9. Inspection of the logs with respect to quality can also be carried out visually at this position, whereby press button signals can be sent to the computer described below. When the wooden object has been turned to a position favourable for sawing, it is gripped by the gripping member 10 at each end, said gripping member suitable being arranged on some form of traverse means. The gripping members are arranged in line with each other and have a width which is less than the distance between the innermost saw cut of the subsequently following saws. The wooden object is passed by the gripping member 10 through an arrangement 11 which, by means of photocells, determines the smallest diameter of said object. Information from the last mentioned arrangement and form the device 7 which determines the quality of the object is passed to a data machine 12 adapted to emit operating signals to operating units 13, 14 and 15 in the sawing plant. When the the wooden object is moved from the arrangement 11 it meets a first array of band saws 16 adapted to saw four trimming cuts throughout the length of said wooden object. The band saw unit 16 is arranged to be controlled by operating unit 13 with respect to the position of the saw cuts, i.e. the mutual positions of the band saw-blades relative to the wooden object. As can be seen a roughly trimmed material is arranged to follow a conveyer belt 17 for further sawing in a band saw machine 18 and is further worked in an edging device 19. The wooden object 1 passed by the gripping members 10 through the first sawing unit 16 now has the form of a block 20 which is deposited on a roller belt 21 and fed into a second array of band saws 22 adapted to be operated by the computer via the operating member 14, with respect to the adjustments of the saw-blades relative to the band 20. The waned or unfinished material, also at this position, is conveyed to the conveyer path 17 to be further worked in the edging apparatus 18 and 19. The remaining portion of the block 20 is fed to an additional band saw unit 23 to be finally sawn up into planks, after which it is moved laterally over to a sorting conveyor 24 past the feed arrangement 25 and the sorting directing plant 26 to a sorting tray 27. The planks are fed from the sorting tray, via a conveyor belt 28, to another conveyor belt 29 where they are moved laterally to a stacking position 30.

The described arrangement enables wooden objects to be sawn up without being pre-sorted in any way and, thereby, obtain the maximum yield of the wood. When the wooden objects have entered the arrangement 7 and pass the arrangement 11 the computer has obtained such information concerning the relevant wooden object that, owing to a pre-determined programming, it can immediately control the various sawing units, via operating units 13, 14 and 15 so that desired cuts are made along the relevent wooden objects. Programming shall be such that consideration is paid to certain definite types of wood, to which the incoming wooden objects can be referred. Each band saw machine is thus adapted so that it can be adjusted in accordance with signals given by the computer. The present invention thus eliminates such work as manual inspection of the Wooden objects, pre-sorting, which results in large storage sites, and from a manual handling respect a difficult adjustment procedure for all the saw arrangements included in the plant. Naturally, within the scope of the invention a plurality of different types of saws can be used and the invention is not restricted to the use of band saws, but, for instance, circular saws can also be used. Neither is the invention restricted to the use of arrangements shown here for determining the diameter and the bowl end or top end of the logs, but that other arrangements suitable for this purpose can also be used. Neither is the method of conveying the wooden objects between the various sawing stations of significance to the present invention.

What is claimed is:

1. A process for sawing an object comprising: radioscopically detecting the quality of said object; photoelectrically detecting the smallest dimension of said object, feeding the quality and dimensional information to a computer; computing the proper positions of a first adjustable band saw in accordance with said quality and dimension information; adjusting said first saw in accordance with signals from said computer; sawing the object with said first band saw; whereby said object is sawed to get the maximum yield of useable lumber consistent with the quality and dimensions of the initial wood object.

2. A process as in claim 1 further comprising before said quality detecting step the steps of detecting any stones and metal embedded along the outer surface of said object and rejecting objects with stones and metal embedded therein.

4 3. A process as in claim 1 wherein the object is a log and further comprising before said quality detecting step the step of debarking the log.

4. A process as in claim 1 further comprising again 5 sawing the object with a second adjustable band saw in accordance with signals from said computer.

5. A process as in claim 1 further comprising selectively rotating said object before said step of photoelectrically detecting the smallest diameter of the object; whereby the object will be in a position favorable for said sawing.

6. A process as in claim 1 wherein said object is a wooden log further comprising:

the following steps before said quality detecting step:

debarking the log; detecting stones and metal embedded along the outer surface of said log; and rejecting logs with stones and metal embedded therein; before said diameter detecting step: rotating said log so that the object will be in a position favorable for said sawing step;

again sawing said log after said first sawing step with a second adjustable band saw in accordance with signals from said computer; thereafter stacking the cut up sections of the log.

References Cited UNITED STATES PATENTS 2,615,484 10/1952 Roberge 144-312 X 3,244,204 4/1966 Sherman 143-468 3,244,206 4/1966 Bossen 144-209 3,259,157 7/1966 Runnion 144112 3,381,729 5/1968 Dunn 144312 DONALD R. SCHRAN, Primary Examiner US. Cl. X.R. 

